If you thought cassette-tape sales were dead, they’re not — they’re just serving life sentences in state prison.

New York prisoners — long professing they got a bum rap — are getting their own music from artists including Jay-Z, 50 Cent, Nas and Jadakiss.

By law, inmates are not allowed to have CDs in prison, but Chris Barrett, a New York marketing executive and a former inmate, has struck a deal to be the exclusive distributor of Universal Records music within the US prison system.

Universal will re-release classic hip-hop LPs on cassette, giving prisoners access to old and new music. Families and friends of inmates can buy them through Barrett’s company, Send A Package, a one-stop shop for inmates that sells everything from food to magazines and clothes.

Barrett orders the tapes in bulk and pays about $6 per tape for Universal to make them from CDs. He sells them for $13 apiece.

Barrett said he has sold about 200 cassettes in the past six weeks.

He launched Send A Package in 2011 so family and friends could send gifts to prisoners that are pre-approved and not opened by prison security.

“When I went to Universal, they said, ‘We’ve been looking for you for 10 years,’” Barrett said. “‘We’ve been looking for ways to get our music in the prison system.’”

Many tissues will be deployed tonight as the tale of “Downton Abbey” (whose denizens include Lady Mary Crawley, played by Michelle Dockery, pictured) reaches the sad season 3 finale. The show’s owners, however, will be counting their good fortunes.

The PBS Masterpiece series garnering as many as 7 million viewers per episode is a co-production of UK production company Carnival Films, owned by NBCUniversal and PBS Distribution, which in turn is owned by PBS and its affiliate WGBH Boston. They all share in the spoils, but trying to figure out who gets what is as murky as Lord Grantham’s own finances.

Fortunately for public broadcasting, PBS holds the US DVD rights and rights to TV and digital distribution. PBS has managed to exploit those rights to their fullest with Netflix, Hulu, Amazon and iTunes all airing parts of the series, though Amazon just bought complete exclusivity for all three seasons.

Meanwhile, PBS’s own website has been cashing in with a long video sponsorship from Ralph Lauren unspooling before each episode.

On Amazon’s website, “Downton” was the third-best-selling DVD box set as of Feb. 15. In the UK, the show is Amazon’s best-selling DVD in history, and seasons 1 and 2 were the most-watched TV seasons on Amazon Prime’s Instant Video service.

Nielsen VideoScan has season 3 of “Downton” ranked second in overall DVD sales for the first week of February.

In addition, the show has been licensed in 100 countries and creator Julian Fellowes is at work on a prequel on Cora and Lord Grantham’s romance that is destined for NBC, according to reports.

What does this all add up to? Our Hollywood sources suggest a show with that level of popularity might cost some of the 100 TV stations that have licensed it around $3.5 million an episode. According to The Numbers website, US DVD sales figures for seasons 1 and 2 were $19.2 million in 2012 and $879,848 in 2013. No figures are available yet for the hugely popular Season 3 DVD.

A PBS spokeswoman would say only that the revenue is shared among Carnival, NBCUniversal and PBS. –Claire Atkinson

Fast tracks

Fast Company, Silicon Valley’s magazine of choice, has issued its list of the 50 most innovative companies.

While it includes tech stalwarts Apple, Microsoft and Google, the list also has some old-line companies that have jump-started their 21st-century mojo. These include Target, “for shrinking the big-box store”; Ford, “for turning a car company into a software leader”; and sleepy Corning, “for becoming the 800-pound gorilla of the touch-screen business.”

There were notable deletions from last year’s list as well, including Facebook and Twitter. But the editors did note the worst 2012 moments for both tech titans.

For Facebook, it was not its initial public offering, but “proudly touting that CEO Mark Zuckerberg helped code Poke, its copy of the teen sexting app Snapchat.”

And in a little more than 140 characters, Fast Company twitted Twitter’s CEO Dick Costolo for “kicking a journalist off Twitter for heckling NBC, its Olympics coverage partner.” –Post staff